Loud crackling noises from audio equipment are often caused by connection problems on the input side or within the controls. Check and clean all plug-in connector with spray contact cleaner…. More of this stuff later. Also move the power lead about a little as sometimes a poor connection here can result this type of noise.

Screw type attachment terminal can also loosen so check them.

If your system has a combined on/off switch and mechanical volume control, this problem could well be dirt in and/or degradation of the volume control pot(potentiometer; it’s a variable resistor with a fancy name). Over time dust can get between the control’s track and wiper contact. If this is the case you will need a can of spray contact cleaner: Radio Shack will have it. You will need to take the covers off the unit to get to the control.

I guess you know this bit but I’ll say it anyway…… disconnect the mains power first. Try to spray the cleaner into the control: there are often openings in the metal case.

The tone controls are also subject to the same problems and the same remedy.

It could be Ground loop hum, if a connection has become loose and is not grounded properly it can cause an annoying static. (this bit can be done plugged in, IF YOUR CAREFUL) If this is a component system then you'll have to disconnect everything and reconnect it one by one until you find the source of the hum and then (do this bit unplugged) check that piece of equipment for wear and tear that looks like it could be making an unnecessary ground (metal on metal connection). Usually this could be caused by the sheath on a cable being worn until the wire in connecting something else.

It's time to speak out for your right to repair

Dear Minnesotans,

Right now, Minnesota has a chance to pass the first Fair Repair bill in the nation.
We have a chance to guarantee our right to repair electronics—like smartphones, computers, and even farm equipment.
We have a chance to help the environment and stand up for local repair jobs—the corner mom-and-pop repair shops that keep getting squeezed out by manufacturers.

We've been working with local repair companies, non-profit refurbishers, and tech-savvy politicians to come up with a solution. And they've done just that — Minnesota is the first state to consider a Fair Repair Bill.

If you agree with us, find out who represents you in the Minnesota House of Representatives.
Tell them you support the bipartisan Fair Repair Bill, HF 1048. Tell them that you believe repair
should be fair, affordable, and accessible.